3rd of 10 Magnetic Separator Myths
On a regular basis, we will receive an enquiry requesting a Magnetic Separator of a specific size. However, it is only when the enquiry also requests a specific gauss figure that it all starts becoming a little complicated.
Frequently, the gauss figure has been added with little understanding of the meaning of ‘gauss’. It is a figure commonly quoted by companies supplying magnetic separators, but what is the relevance? Is 100,000 gauss better than 10 gauss?
‘Gauss’ is the cgs (centimeter-gram-second) unit of measurement of a magnetic field, which is also known as the ‘magnetic flux induction’ or the ‘magnetic induction’. One gauss is equal to one Maxwell per square centimeter.
But does that really help or simply add to the confusion? And does it help a purchaser understand if one Magnetic Separator is stronger than another?
There are several inherent problems with basing a magnetic separator purchasing decision on the ‘gauss’ value alone. These include:
- How do you know that the Magnetic Separator you are purchasing actually has the quoted level of gauss?
- Even if you have a gauss meter to measure the gauss, have you been trained how to correctly use it?
- Where on the Magnetic Separator is that highest gauss reading, as different levels of gauss will be found at various points on the Magnetic Separator?
- The ability of the Magnetic Separator to capture metal particles is not only a function of gauss alone and, in many cases, higher gauss Magnetic Separators will not provide the best metal separation;
In fact, if the word ‘gauss’ is swapped for ‘elephants’ they may be equally relevant. This is only because a value is meaningless unless it is quantifiable. A request for a Cartridge or Tube Magnet with 11,000 gauss on the surface could be perceived as having the same meaning as asking for one stated as having the strength of 11,000 elephants. This is only because the ‘gauss’ figure is exceptionally difficult or impossible for a customer to actually measure.
However, help is at hand! There is a simple way to assess and measure the magnetic attractive force on a Magnetic Separator. Undertaking a physical test at least partly removes the ‘gauss’ reading from the assessment. The process is simple:
- Use a Spring Balance with a 3mm steel ball on the end;
- The Steel Ball is placed on the surface of the Magnetic Separator;
- The Steel Ball is then pulled away and off the Magnetic Separator;
- A reading is taken on the Spring Balance (in kilogrammes). This is the break away force;
- The test is repeated at several locations on the Magnetic Separator;
By conducting this test, you know have a real tangible figure than means something. You can conduct the same test on other Magnetic Separators and then you will be able to confirm which Magnetic Separator requires the highest kg force to extract the Steel Ball from the Magnetic Field.
As part of the internal auditing system, the Magnetic Separator test can be repeated at regular intervals to ensure that the Magnetic Separator is not losing strength. It is a simple and very effective method of assessing the magnetic strength of smaller Magnetic Separators and doesn’t need extensive training using costly and high tech equipment.
So, when requesting a price for a Magnetic Separator, it is recommended that you ask for the number of kilogrammes needed to pull the 3mm steel ball from the surface and, when you receive the equipment, test it to check that what you have purchased is what was ordered.
Interestingly, many of our customers have found that some Cartridge or Tube Magnets with high quoted ‘gauss’ figures actually need less kilogrammes of force to remove the steel ball from the surface of the Magnetic Separator. In reality, this means that they are magnetically weaker than those with lower gauss figures. Now, isn’t that rather odd?
Magnetic Separator Myth 1 – Should You Always Use the Strongest Magnet?
Magnetic Separator Myth 2 – Are all Rare Earth Magnetic Separators the Same?
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